In-Service Performance Evaluation of Guardrail End Treatments (2018)

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Committee for Study of In-Service Performance of W-Beam Guardrail End Treatments, Phase 1 In-Service Performance Evaluation of Guardrail End Treatments TRANSPORTATION RESEARCH BOARD SPECIAL REPORT 323

Transportation Research Board Special Report 323 Subscriber Categories Administration and management; design; highways; maintenance and preservation; research; safety and human factors Transportation Research Board publications are available by ordering individual publications directly from the TRB Business Office, through the Internet at www.TRB.org or national academies.org/trb, or by annual subscription through organizational or individual affiliation with TRB. Affiliates and library subscribers are eligible for substantial discounts. For further information, contact the Transportation Research Board Business Office, 500 Fifth Street, NW, Washington, DC 20001 (telephone 202-334-3213; fax 202-334-2519; or e-mail TRBsales@ nas.edu). Copyright 2018 by the National Academy of Sciences. All rights reserved. Printed in the United States of America This publication was reviewed by a group other than the authors according to the procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the National Academy of Medicine. This study was sponsored by the National Cooperative Highway Research Program. Library of Congress Cataloging-in-Publication Data Names: National Academies of Sciences, Engineering, and Medicine (U.S.). Committee for Study of In-Service Performance of W-Beam Guardrail End Treatments, Phase 1, author. | National Academies of Sciences, Engineering, and Medicine (U.S.). Transportation Research Board, issuing body. Title: In-service performance evaluation of guardrail end treatments/ Committee for Study of In-Service Performance of W-beam Guardrail End Treatments, Phase 1, Transportation Research Board. Other titles: Special report (National Research Council (U.S.). Transportation Research Board); 323. Description: Washington, DC: National Academies of Sciences, Engineering, and Medicine, Transportation Research Board, 2017. | Series: Transportation Research Board special report ; 323 Identifiers: LCCN 2017025882 | ISBN 9780309460200 (alk. paper) Subjects: LCSH: Roads—United States—Guard fences—Testing. | Traffic safety—United States—Evaluation. | Roads—United States—Safety measures—Evaluation. Classification: LCC TE228 .N297 2017 | DDC 625.7/95—dc23 LC record available at https://lccn.loc.gov/2017025882

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v COMMITTEE FOR STUDY OF IN-SERVICE PERFORMANCE OF W-BEAM GUARDRAIL END TREATMENTS, PHASE 1 Hugh W. McGee, Sr., Annandale, Virginia, Chair Linda Ng Boyle, University of Washington, Seattle James E. Bryden, Delmar, New York Douglas J. Gabauer, Bucknell University, Lewisburg, Pennsylvania Shauna Hallmark, Iowa State University, Ames David Harkey, University of North Carolina at Chapel Hill Douglas W. Harwood, MRIGlobal, Kansas City, Missouri Thomas Hicks, Century Engineering, Inc., Hunt Valley, Maryland Cing-Dao Kan, George Mason University, Fairfax, Virginia Susan Martinovich, CH2M Hill, Carson City, Nevada Priyaranjan Prasad, Plymouth, Michigan C. Shane Reese, Brigham Young University, Provo, Utah Omar Smadi, Iowa State University, Ames Transportation Research Board Staff Joseph R. Morris, Study Director

vii Preface The Transportation Research Board formed the Committee for Study of In-Service Performance of W-Beam Guardrail End Treatments, Phase 1 to develop methods for in-service evaluation of the performance of guardrail end treatments in crashes. Guardrail end treatments are intended to reduce the risk of injury to vehicle occupants in a highway crash in which the ve- hicle strikes the end of a length of guardrail. The performance of guardrail end treatments and other roadside devices is evaluated by laboratory crash testing. The purpose of the committee’s study was to aid highway agencies in supplementing crash testing with evaluation of the devices in use on roads to ensure their safety. The committee included members with expertise in highway safety research, research design, statistics, highway safety programs, structural engineering, and simulation modeling. The study was sponsored by the National Cooperative Highway Research Program. The committee received presentations at its meetings from Mark Burkhead, Pennsylvania Department of Transportation; Monique Evans, Federal Highway Administration; King Gee, American Association of State Highway and Transportation Officials; Brelend Gowan; Michael Griffith, Federal Highway Administration; Scott King, Kansas Department of Trans- portation; Kevin Lee, Nevada Department of Transportation; Malcolm Ray, RoadSafe LLC; Maria Ruppe, City of Columbus, Ohio; and Dean Sicking, University of Alabama at Birmingham. In addition, the committee commis- sioned three resource papers from the following authors: Chad Heimbecker and Eric Lohrey, Brian Wolshon and Anurag Pande, and Bhagwant Persaud.

viii PREFACE The papers are discussed in Appendix A, where links to the papers are provided. This publication was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the Report Review Committee. The purpose of this independent review is to provide candid and critical comments that as- sist the authors and the National Academies of Sciences, Engineering, and Medicine in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The contents of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. The following individuals participated in the review of this report: Chandra Bhat, The University of Texas at Austin; E. Dean Carlson, Carlson Associates; Keith Cota, New Hampshire Department of Transportation; H. Clay Gabler, Virginia Polytechnic Institute and State University; William Thomas Hollowell, WTH Consulting LLC; Sandra Larson, Iowa Department of Transportation; Fred Mannering, University of South Florida; Sue McNeil, University of Delaware; John Milton, Wash- ington State Department of Transportation; and Kathryn Zimmerman, Applied Pavement Technology, Inc. Although the reviewers provided many constructive comments and suggestions, they were not asked to endorse the committee’s conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Susan Hanson, Clark Uni- versity, and by Paul Jovanis, The Pennsylvania State University. They were responsible for making certain that an independent examination of the report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution. Joseph R. Morris managed the study and drafted the report under the guidance of the committee and the supervision of Stephen R. Godwin, Director, Studies and Special Programs. Karen Febey managed the report review process. Janet McNaughton edited the report and Jennifer J. Weeks prepared the prepublication manuscript and background papers for Web posting, all under the supervision of Javy Awan, Director of Publications. Timothy Devlin and Claudia Sauls assisted with meeting arrangements and communications with committee members.

ix Contents Summary 1 1 Study Charge and Origin 9 Committee’s Task, 10 Objectives of In-Service Evaluation, 12 Evaluation Methods, 23 Organization of the Report, 26 2 Methods of Measuring Performance 28 Comparative Evaluations, 28 Descriptive Evaluations, 51 3 Nationally Coordinated Evaluation Research 55 Evaluation Objectives, 56 Sources for Evaluation Procedures, 57 Validating Crash Test Procedures, 58 Evaluation Methods for Routine Highway Agency Use, 66 Impact of Design, Installation, and Maintenance Practices on Performance, 67 Planning and Organization, 70 Annex 3-1: Summary of Procedural Guides to In-Service Evaluation of Roadside Safety Devices, 77

x CONTENTS 4 Routine In-Service Evaluation of Roadside Devices 94 Objectives of Routine Evaluations, 94 Obstacles to Evaluation, 95 Strengthening Highway Agency Capacity to Conduct Evaluations, 96 Role of a Nationally Coordinated Demonstration, 100 5 Conclusions and Recommendations 104 Conclusions, 104 Recommendations, 110 Appendixes A Commissioned Papers 119 B Glossary and Illustrations of Guardrail End Treatments and Other Roadside Safety Devices 122 Study Committee Biographical Information 129